Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for 3C 273: 02-17 (93), 02-18 (93), 02-19 (93), 02-20 (93), 02-21 (93) — by astronomy; check the weather when the night is within four days.

2047-02-13astronomy score per night — click a bar for that night2047-03-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-02-13 Wed	31	—	unknown	23:20–05:45 (marginal, 6.42 h)	50.1° 03:15	10.33	85%	10.9°
2047-02-14 Thu	46	—	unknown	23:00–05:45 (marginal, 6.75 h)	50.1° 03:15	10.29	76%	21.7°
2047-02-15 Fri	83	—	unknown	23:20–03:50 (good, 4.5 h)	50.1° 03:10	10.25	65%	35.1°
2047-02-16 Sat	90	—	unknown	23:20–05:45 (good, 6.42 h)	50.1° 03:05	10.21	54%	48.7°
2047-02-17 Sun	93	—	unknown	23:15–05:40 (good, 6.42 h)	50.1° 03:00	10.17	43%	62.3°
2047-02-18 Mon	93	—	unknown	23:10–05:40 (good, 6.5 h)	50.1° 02:55	10.13	32%	75.7°
2047-02-19 Tue	93	—	unknown	23:05–05:40 (good, 6.58 h)	50.1° 02:55	10.09	22%	88.9°
2047-02-20 Wed	93	—	unknown	23:00–05:40 (good, 6.67 h)	50.1° 02:50	10.04	14%	101.8°
2047-02-21 Thu	93	—	unknown	23:00–05:35 (good, 6.58 h)	50.1° 02:45	10.0	8%	114.6°
2047-02-22 Fri	93	—	unknown	22:55–05:35 (good, 6.67 h)	50.1° 02:40	9.96	3%	127.1°
2047-02-23 Sat	93	—	unknown	22:50–05:35 (good, 6.75 h)	50.1° 02:35	9.92	1%	139.3°
2047-02-24 Sun	93	—	unknown	22:45–05:35 (good, 6.83 h)	50.1° 02:35	9.87	0%	151.1°
2047-02-25 Mon	93	—	unknown	22:45–05:30 (good, 6.75 h)	50.1° 02:30	9.83	1%	162.1°
2047-02-26 Tue	93	—	unknown	22:40–05:30 (good, 6.83 h)	50.1° 02:25	9.79	4%	169.9°
2047-02-27 Wed	93	—	unknown	22:35–05:30 (good, 6.92 h)	50.1° 02:20	9.74	9%	167.0°
2047-02-28 Thu	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.1° 02:20	9.7	15%	157.3°
2047-03-01 Fri	93	—	unknown	22:30–05:25 (good, 6.92 h)	50.1° 02:15	9.65	23%	146.3°
2047-03-02 Sat	93	—	unknown	22:25–05:25 (good, 7.0 h)	50.1° 02:10	9.61	31%	134.9°
2047-03-03 Sun	93	—	unknown	22:25–05:20 (good, 6.92 h)	50.1° 02:05	9.56	40%	123.3°
2047-03-04 Mon	93	—	unknown	22:25–05:20 (good, 6.92 h)	50.1° 02:00	9.51	50%	111.4°
2047-03-05 Tue	92	—	unknown	22:30–05:20 (good, 6.83 h)	50.1° 02:00	9.47	60%	99.1°
2047-03-06 Wed	89	—	unknown	22:35–05:15 (good, 6.67 h)	50.1° 01:55	9.42	70%	86.6°
2047-03-07 Thu	85	—	unknown	00:10–05:15 (good, 5.08 h)	50.1° 01:50	9.37	79%	73.6°
2047-03-08 Fri	81	—	unknown	03:05–05:15 (good, 2.17 h)	50.1° 01:45	9.32	87%	60.1°
2047-03-09 Sat	44	—	unknown	22:15–05:10 (marginal, 6.92 h)	50.1° 01:40	9.28	94%	46.3°
2047-03-10 Sun	28	—	unknown	01:00–05:10 (marginal, 4.17 h)	50.1° 01:40	9.23	98%	32.3°
2047-03-11 Mon	24	—	unknown	01:35–05:10 (marginal, 3.58 h)	50.1° 01:35	9.18	100%	18.7°
2047-03-12 Tue	25	—	unknown	21:55–05:05 (marginal, 7.17 h)	50.1° 01:30	9.13	99%	9.7°
2047-03-13 Wed	33	—	unknown	21:30–05:05 (marginal, 7.58 h)	50.1° 01:25	9.08	95%	17.0°
2047-03-14 Thu	71	—	unknown	21:35–22:00 (good, 0.42 h)	50.1° 01:25	9.03	88%	30.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-02-13&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.